Internal combustion engine



sept. 23, 195s L. ELSBETT 2,853,061

INTERNAL COMBUSTION ENGINE l Filed April 1.1, 1957 gf# y %/fc /5 d /5 /4/fa y 2d e if Q y Ze Q Z4 //Z N INVEN TOR.

United States Pater Zjil Patented Sept. 23, 195@ INTERNAL CMBUSTIONENGlNE Ludwig Elsbett, Salzgitter-Bad, Germany, assigner to WolfgangHenry Richard Behrens, Cologny-Genf, Switzerland Application April 11,1957, Serial No. 652,251

Claims priority, application Germany April 19, 1956 4 Claims. (Cl.12S-41.17)

The present invention relates to internal combustion engines.

More particularly, the present invention relates to a scavenged internalcombustion engine in which burned gases are removed from a cylinderafter a work stroke.

rfhere exist scavenged internal combustion engines in which scavengergas is supplied through the intake port or ports of a cylinder for thepurpose of removing burned gases after a work stroke. The ports arecontrolled by the piston which reciprocates within the cylinder so thatthe ports are alternately closed and opened. ln order to avoid excessivepressure iluctuations during operation of the engine due to thealternately open and closed cylinder ports, suitable venting means aresometimes provided through which gas supplied by a blower or othersource of pressure may escape at such times as the cylinder intake portor ports are closed. Thus, the gas sup plied by the source of pressureis wasted. Also, in such arrangements the gas located near the inletport or ports is, during the time these ports are closed, relativelystationary and is therefore heated while waiting to enter into theinterior of the cylinder. As a result only pre-heated gas enters thecylinder once the ports are open, thereby destroying any cooling effectwhich might otherwise be obtained from the scavenger gas.

It is therefore an object of the present invention to provide ascavenged internal combustion engine which overcomes the abovedisadvantages.

It is another object of the present invention to provide a scavengedinternal combustion engine in which the scavenger gas is efiicientlyused for cooling purposes.

With the above objects in View, the present invention mainly consists inthat improvement in a scavenged internal combustion engine whichcomprises a cylinder formed with spaced intake and exhaust port means,blower means for blowing gas in excess of the quantity required forscavenging, first liow guide means arranged exteriorly of the cylinderin the region of the intake port means and communicating with the blowermeans, and second flow guide means extending through that portion of thecylinder which is in the region of the exhaust port means thereof andcommunicating with the first ow guide means at a point downstream of theintake port means. As a result, when the intake port means are open gasblown by the blower means is blown into the cylinder, thereby scavengingthe same, and when the intake port means are closed gas blown by theblower means is moved past the intake port means and through theabove-mentioned portion of the cylinder in the region of its exhaustport means, thereby cooling this portion of the cylinder.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. The'invention itself, however, bothas to its construction and its method`of operatiomtogether with additional objects and advantages thereof,will be best understood from the following description of speciiicembodiments when read in connection with the accompanying drawing, inwhich the figure is a sectional elevational view of an internalcombustion engine incorpoi-ating a scavenging system according to thepresent invention.

Referring now to the drawing, there is shown a piston 1 slidablyarranged within a cylinder 2 and connected to a crank shaft 3 by meansof a piston rod 4. The cylinder 2 has an end portion including an endwall 2a formed with an exhaust port 2b which communicates with theexhaust 2c, a suitable valve seat 5 being provided for receiving a valveo. The latter is constantly urged to its closed position by a spring 7,and a suitable cam mechanism (not shown) is provided for periodicallymoving the valve to its open position against the action of the spring7.

The cylinder 2 also has a side wall 2d which is formed with intake ports2e that are axially spaced from the end wall 2a. An annular housingportion or flow guide S encompasses the cylinder 2 in the region of theintake ports 2e so as to form an annular channel 9 which is incommunication with a blower 1t) so that gas blown by the blower will bedirected toward and into the intake ports 2e, as shown by arrows a.

Another annular housing portion or flow guide 11 encompasses thatportion of the cylinder 2 which is intermediate the intake ports 2e andthe end wall 2a so as to form an annular jacket 12. The annular channel9 and the annular jacket l2 are separated by a transverse wall portioni3 which extends but partway across to the cylinder 2, so that anannular slot 14 is formed the inner diameter of which is equal to theouter diameter of the cylinder 2. Thus, the lower end of the jacket 12is in cornrnunication with the channel 9 by way of this slot 14, andinasmuch as substantially all of the gas blown by the blower l@ movespast the intake ports 2e before flowing through the slot 14, the latteris located downstream of these intake ports 2e. As a result, gas blownby the blower lil is blown through the ports 2e when the latter are openas indicated by the arrows b, thereby scavenging the cylinder 2, whereaswhen the ports are closed by the piston 1, gas blown by the blower willbe moved past the ports 2e and thence through the slot 14 into theannular jacket 12 as indicated by the arrows c, thereby cooling theouter surface of the intermediate portion of the cylinder 2.

The cylinder 2 is formed with additional conduit means i5 which extendthrough that portion of the cylinder which is in the region of theexhaust port 2b. The conduits l5 communicate at one end thereof with theupper end of the jacket 12 and at the other end with the exhaust 2c.Thus, gas iiowing through the jacket l2 will pass through the conduits15 and thence into the exhaust 2c as indicated by the arrows d. In thisway, not only will the intermediate portion of the cylinder 2 but alsothat portion of the cylinder which is in the region of the exhaust port2b be cooled.

By virtue of the above arrangement, gas is continuously moved past theinlets 2e, even when the same are temporarily closed by the piston 1.Consequently, the air will not be pre-heated during the time elapsedbetween the arrival of a mass of air at the intake ports 2e and theopening of the ports by the piston 1, so that only non-preheated gas isintroduced into the interior of the cylinder 2 through the intake ports.In this way, a substantially greater cooling eect is obtained from thescavenger gases than in constructions wherein no means are provided forinsuring the continuous flow of gases past the cylinder intake ports.Moreover, the continuous flow of gas past the intake ports prevents theaccumula tion of deposits on the cylinder 2 in the region of its intakeports.

Additionally', the use of scavenger gases to cool the exterior of thecylinder 'greatly'improves the' efliciency of an internal combustionengine'in comparison to constructions wherein -in order to avoidpressure fluctuation of the scavenger gases the same a're simply ventedto atmosphere.

It has been found desirable to provide blower means capable of blowing aquantityvof gas which is in excess of that quantity of gas required forscavenging the cylinder. This excess quantity of gas may then be usedfor cooling not only the exterior of the cylinder but also the interiorthereof as well as the piston. Preferably, the quantity of gas should beso selected that the cylinder and the upper fac'e 1 of the piston willbe cooled to the temperature normally prevailing in the cylinder at thebeginning of the work stroke.

Ithas also been found desirable to mount the piston in such a mannerthat when it occupies its lowermost position (whichis the position shownin the gure) the uppcnface 1 of the piston is 'substantially ilush withthe lowermost edges 2e' of the intake'ports 2e'. In this way, thescavenger gases entering through the ports 2e will ow along the upperface 1. This cooling effect may be enhanced by providing at least twodiametrically opposite intake ports 2e.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofscavenged internal combustion engines differing from the types describedabove.

While the invention has been illustrated and described as embodied in aninternal combustion engine with a separate scavenger gas blower, it isnot intended to be limited to the details shown, since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention. For example,.thecrankcase compression of the cylinder or any other suitable pressuresource may be used to move the scavenger gases.

Without further analysis, the foregoing will so fully reveal the gist ofthe present, invention that others can by applying current knowledgereadily adapt it. for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.v

What is claimed as new and desired to be secured by Letters Patent is: Yi

l. Ina scavenged internal combustion engine, in combination, a cylinderhaving an end wall formed with exhaustport means and a side wall formedwith intake port means axially spaced from said end wall; blower means;rst iiow guide means arranged exteriorly of said cylinder `in the regionof saidintake port means and communicating with said blower means; andsecond flow guide means extending through that portion of said cylinderwhich is in the region of said exhaust port means thereof, encompassingsaid cylinder throughout substantially that portion of its length whichis intermediate said intakeport means and said end wall andcommunicating with said first guide means at a point downstream of saidintake port means, whereby when `said intake port means are open gasblown by said blower means is blown into said cylinder therebyscavenging the same, and when said intake port Vmeans are closed gasblown by said blower means is movedpast saidv intake port means, alongthe outer surface of said portion of `said cylinder which isintermediate said intake'port means and said end wall and through saidportion of said cylinder in said region of said exhaust port meansthereof, thereby cooling both of said portions of said cylinder.

2. in a scavenged internal combustion engine, in combination, a cylinderhaving an end wall formed `with said jacket communicating' at that endthereof vwhich isy near said intake port means with said flow 'guidemeans; and conduit means extending through that portion of said cylinderwhich is in the region of said exhaust port means thereof, said conduitmeans communicating at one end with the end of said jacket which isnearsaid end wall, and at the other end with'said exhaust which s incommunication with said exhaust port means, whereby when said intakeport means are Vopen gas blown by said blower means is blown into'saidcylinder thereby scavenging the same, and when said intake port means'are closed gas blown by said blowermeans is Vmoved past said intakeport means and through said jacket and said conduit means into saidexhaust,l thereby cooling lboth of said portions of said cylinder."v

3. in' a scavenged internal combustion engine, in combination, acylinder having anend wall formed with ex'- haust port means and a sidewall formed with intake port means axiallyspaced from said endwalhand anexhaust portion adjacent said end wall'and formed with an exhaustcommunicating with saidl exhaust port means; blower means; flow guidemeans arranged exteriorly of said cylinder in the region of saidintakeport-means and communicating with said blower means; an'annular jacketencompassing that portion of saidcylinder which is intermediate saidintake port means and said end wall, said jacket being formedat that endthereof which isnear said intake port means with an annularslotll'theinner diameter of which is substantially equal tftheouterdiameter of said cylinder so that said jacketls incommunication withsaid ow guide meansY by wayf'of said "annular slot;

and a conduit means'extendin'g' through that` portion of` said cylinderwhich is in thefregion of saidl'exhaust port means thereof, saidconduitmean'scommunicating'at: one end with the end'of said jacket whiehis near" said end wall, and at the otherend withisa'id exhaust*which isin communication with saidfexhaulst port means, whereby when said intakeport means are'open'f'gas blown by said blower means is blown into saidthereby scaveng#v ing the same, and when said intake port means Vare'closed' gas blown by said'blower means is niovedpast said intake portmeans and through said jacket and 'said "conduit means into saidexhaust; thereby cooling both of said portions of said cylinder. A

4. In a scavenged internal combustion engine, in combination, a cylinderhaving an end portion'formed with exhaust port means and a side wallformed with intake port means axiallyspaced from said end portion;blower means operatively associated with said cylinder lfor blowing aquantity of gas through said' intake port means thereof which isapproximately "so much in excess of the quantity ofA gas required foryscavenging said cylinder that said cylinder is cooled byy gas Iblownl bysaid blower means to the temperature normally prevailing in saidVcylinder at the beginning of the work'jstroke; rst flow guide meansarranged exteriorly of said cylinderl in the region of said 'intake'port I'means and communicating with said blower means; and second owguide means extending through said end portion of saidA cylinder andencompassing said cylinder throughout substantially that portionA ofvits length which' is intermediate said 'intake port means and saidendportion and' communicating with said rst guide Ameans at apointfdownstream of said intake port means, whereby when-said intakeport means are open gas blown'vby"v said blower means 'is blown vintosaid cylinderthereby; scavenging and cooling References Cited in the leof this patent UNITED STATES PATENTS 2,179,709 Brecht Nov. 14, 1939 52,775,470 Bixler et a1 Dec. 25, 1956 FOREIGN PATENTS 588,658 France Feb.5, 1925

